Yarn winding



W. F. HICKES YARN WINDING April 4, 1944.

3 Sheets-Sheet 2 Filed Jan. 15, 19,41

` Y ECJ INVENTOR.

ATTORNEY 3 Sheets-Sheet 3' III g YARN WINDING W. F. HICKESv Filed Jan. l5, 1941 mmm April 4, 1944.

Patented Apr. 4, 1944 YARN WINDmG Willis F. Hickes, Snyder, N. Y., assignor to E. I. i du Pont de Nemours & Company, Wilmington,

Del., a corporation of Delaware Application January 15, 1941, serial No. 374,453

(c1. 24a- 4er l 10 Claims.

This invention relates to the Winding of yarn on to a rotating spool or bobbin ,to form a crosswound package. More particularly, it relates 4to the winding of yarn lon a winding apparatus wherein the traversing yarn guide is maintained spaced from the surface of the wind-up package. The invention is particularly applicable to the winding mechanism employed in the manufacture or treatment of artificial filament yarn which is to be wound around a rotating support, for example, inthe manufacture of viscose rayon by the bobbin process.

According to the bobbin process for the manufacture of viscose rayon yarn, the freshly formed yarn leaving the spinning bath is collected in package form on a rotating perforated spool or bobbin, the fully Wound package being subjected in later operations to treatment with various liquids by pressure or suction means to yield a purified yarn suitable for use in the textile art. It is necessary that the yarn package be uniformly porous and liquid permeable so that this liquid treatment may proceed to a uniform extent and in a rapid and economical manner. To obtain such a package, the industry has utilized a Winding apparatus that traverses the yarn along the length of the support bobbin to form a crosswound package wherein the yarn is wound in a. helical manner rather than in the ribbon wind manner typical of the spoollng art. Because the freshly formed yarn being Wound on to the rotating bobbin is very susceptible to mechanical damage, the traverse guide is generally maintained spaced from the surface of the wind-up package. It is not possible to employ a precision wind apparatus of the type employed when winding the completely finished yarn on to cones or similar types of packages.

Because of this spacing of the guide from the surface of the package, the yarn passing thereto lags behind the guide and is wound on to the bobbin, or other yarn support, at a point some distance behind the momentary position of the guide, this distance being determined bythe spacing of the guide from the surface of the package and by the wind-ratio employed. This latter term indicates the number of revolutions made by the bobbin for each complete cyclical4 or back-andforth movement of the yarn traverse guide. This lag of the yarn behind the guide is of no real significance when the guide is moving along the mid portion of the length of the bobbin package, since the yarn at such a `time follows the movement of the guide perfectly and is laid down evenly on the bobbin, although at a distance behind the guide. This flag is vof real significance,

, however, at the moment when the guide reaches tain more yarn per bobbin surface than does the middle portion of the package, and they are also more dense because they are formed at a moment when the angle of yarn lay-down is changing and the yarn is, therefore, being wound at a very low helical angle. These two effects (uneven cake thickness and denseness) Vboth serve to hinder the subsequent liquid treatment of these end portions of the yarn package and make their purification more difficult.

. In previously known winding apparatus, the industry employed a single cam mechanism that imparted a simple harmonic motion to the traverse guide. The yarn packages produced by such a mechanism possessed very large shoulder ridges and were very dimcult to purify. To correct this situation, it was proposed to shorten the stroke of the traverse guide to a length less than that of the final package and shift the origin of the traverse stroke along the length of the package by imposing a secondary motion on the stroke of the guide.A Thus, a greater proportion of the yarn would be wound into the central portion of the package and the formation of the undesirable shoulder ridges would be avoided. However, the yarn lengths wound on to the package at the reversal points of the guide stroke were still laid down at a low helical angle and the wound packages contained dense portions that impaired their subsequent purification. Furthermore, the mechanism necessary to impart this secondary motion to the traverse guide was expensive to construct and maintain in operating condition.

It has also been suggested heretofore that the traverse cam mechanism be designed to impart an inverse harmonic motion to the traverse guide, whereby the guide would move at a uniform and constant velocity throughout all portions of its stro-ke save those portions immediately preceding and following each reversal point 'during which portions the guide moved at a greatly increased velocity.. Here too, however, it was necessary to impose a secondaryl motion on the stroke of the guide in order to form a yarn package free of the undesirable shoulder ridges.

It is an object of this invention to provide an improved traverse mechanism for use with a winding apparatus wherein'the traverse guide is mounted spaced from the surface of the wind-up package, which mechanism will form a yarn package that is eminently suited for lsubsequent liquid i treatment.

ments.

ena of the bobbin. The une A-B-B1 designates the path of movement of the traverse guide at l the extreme circumferential end of the bobbin.

It will be noted that the yarn lay-down lags behind the path of travel of the traverse guide.

When the traverse guide is at point B-I, the

The objects of this invention are accomplished,

stroke in either direction except for a short period immediately following each reversal, during which period the said guide is moved at a higher velocity. By virtue of this short rapid movement of higher velocity immediately after each reversal, the guide is able to overcome the effect of yarn lag that normally occurs at these-reversal points and thus prevent the formation of undesirably high ridges in the shoulder portions of the yarn package.

The following description. of the invention will be more readily understood if taken in connection with the accompanying drawings, wherein:

Figures l, 2, and 3 are surface developments of one extreme end of a bobbin showing the movement of the traverse guide and the thread lay-down on the developed surface of the bobbin,

when the traverse guide is spaced from the bobbin, under different conditions of yarn traverse.

Figure 4 is a diagrammatic side elevational view showing an apparatus for the winding of a freshly spun yarn on a bobbin.

.Figure 5 is a front elevational view ,of a yarn Winding apparatus constructed in accordance with the elemental features of the present invention.y

Figure 6 is an-enlarged front elevational view of a plate 'cam suitable for use in the present invention.

Figure 7 is a graphic illustration showing the 'basic elements of yarn traverse.. in accordance with the present invention.

Figure 8 is a diagrammatic front elevational view, with the bobbin in section, of the improved yarn package formation obtained by use of the present invention.

Figure 9 is a side elevational view, with parts shown in section, of a modified form. of yarn traversing mechanism. 4

Figure 10 is a front elevational view taken along the line I 0|0 of Figure 9.

Figure 1 of the drawings illustrates biy surface development of one extreme end of the bobbin, theline of yarn lay-down and the path of move# ment of'a traverse guide when using a. traverse guide spaced from the bobbin and having a uniof yam lay-down on one extreme circumferential yarn Will be laid down on the bobbin at the point A-I. As the traverse guide movesfrom B-I to B2, B--3 B-I3, the yarn is laid down on the end of the bobbin at the corresponding points A-l, A-2, A-3 A-I3. The numbers referred to in the drawings, both as to yarn laydown and traverse guide movement, designate equal increments of time. Thus, as the travel of the traverse guide reverses at the point B the yarn is laid down on the bobbin over a low helix angle. As a consequence, more yarn, per bobbin surface, will be laid down on the end of the bobbin -thanon other sections of the bobbin 'resulting in high shoulderv ridges at the twoextreme ends of the package. f

Figure 2 illustrates, by similar surface development of one extreme end of the bobbin, the theoretical yarn lay-down in an ideal situation (Aunobtainable) where thetraverse guide moves to one extreme position B of its traverse stroke and then, after reversal, instantaneously moves from the point B" to the point B1. Under such ideal conditions, the thread would have a sharp change in direction at the point A, A1. Thus, if such an ideal situation were possible, a package would be formed having straight-sided ends and having a uniform thickness yand density throughout.

Figure 3 of the drawings is another similar surface development of one extreme endof the bobbin showing the line of yarn lay-down and the path of movement of a traverse guide when using a traverse movement which is uniform throughout its entire traverse stroke except for an increased traverse speed over a short distance of the length of its traverse strokes beginning immediately after reversal of direction. Under this situation the ideal situation referred A to in Figure 2 is closely approached. As will be noted by the line A-B, the traverse arm moves in a uniform direction to one extreme end B of its stroke, and then the speed of traverse is increased, as illustrated over the time increments B1, B2, B3, and B4. As a result, the yarn lay-down changes direction much more quickly than in the case of a traverse movement as illustrated in Figure 1. As a result, the yarn can be laid down on the package with a slightly rounded end but with a uniform thickness and density as hereinafter referred to with reference to Figure 8 of the drawings. f

Referring to Figure 4-of the drawings, the yarn I formed by the oextrusion of a, spinning solution into a spinning bath contained in. trough 2 is led through the bath for a suitable distance by guide 3, and is then passed upwardly to the rotating bobbin 4. The yarn is traversed back and forth across the face of the bobbin by the oscillating traverse guide 5 so as to form the desired yarn package 6. As shown in the drawings the. guide 5 is so mounted on the lower end of the oscillating arm I0 that it is spaced from the surface of the bobbin lby the' distance X. The traverse arm is oscillated by means of oscillating horizontal rod H which is xedly attached to the arm I 0. The rod Il is supported in bears ings l2 and is caused to oscillate through a small arc by means of a cam mechanism contained in compartment 3|. The rod Il and the arm I0 are oscillated over an arc which will be suflicient to move the yarn along the desired length of traverse across the face of bob bin 4.

Figure illustrates a cam mechanism which i speed in the opposite direction followed by a substantially uniform speed in the same direction, then immediately after again reversing the direction an increased speed in the frstfnamed direction followed by the first-named movement; the two lower `speeds being substantially uniform and equal, and over the major portion of the travel of the member 23, the two higher speeds also being substantially uniform and equal but 'over a minor portion of the travel of the member 23. The member 23 is provided with slots 24 and-guide pins 25 whereby to maintain the same in vertical reciprocation. The member 23 is also provided with a slot 21 in`whichv may be positioned guide )pin 28 for theoscillation of arm 26 which is flxedly attached to rod II,- and imparts to the latter an oscillating motion.vv Figure 5 shows the member 23 in its extreme top posi By rotating the cam 20 in the direction of the arrow about the cam shaft 2 I, the cam followers 22-22, which are attached to themember 23, will b e made to follow the cam outline' and reciprocate the member 23 in the following manner: First, with a relatively high speed in a. downward direction over a short length of its travel,.

line numbered AI--3 is drawn through the two oppositely disposed points of reversal ofldirection of the cam surface. 2 4 is drawn into the points of speed change; or of cam surface slope change. The two lines divide the cam surface through four sections,`

A, B, C, and D. The cam surface slope of Asection A is substantially equal and'opposite to the cam slope of section C and thecam slope of section B is substantially equal and opposite to the cam slope of section D. As a'result, as the cam followers move over the slopes of the cam surface;

the above-mentioned alternate speeds will be imparted thereto. Preferably, each` of the high speed sections A and C of cam 20 cover not to exceed 30 of the cam surface. Consequently, the high speed oft'raverse of member 23 immedi ately after reversal will take place not to exceed over 1/6v `of its travel. In order to obtain substantially uniform reciprocal motion from a uniform rotary motion of the cam, the curved The line numbered surfaces of the cam will be drawn along the lines of a spiral of Archimedes. q

The sections of the cam surfacewhich impart the higher speed to the cam followers are preferably so sloped that the speed of the cam followers will be at least 20% faster than the speed imparted thereto by the lower speed sections of the cam. With a wind ratio of approximately 4 and a spacing between the traverse guide and the bobbin of approximately 1/ inch, it is preferred that the speed of the follower as it travels over the high speed sections of the cam is at least higher than the speed of the follower as it travels over the slow speed sections of the cam. It will be noted that the cam surface at the two points of juncture of line I.-3, the points of reversal of direction of the cam follower, are curved instead of sharply outlined. As a result, the reversal of direction, although not instantaneous, will be as nearly instantaneous as is consistent with operability of the cam mechanism from a maintenance standpoint.

Figure 7 of the,drawings illustrates graphically the nature of the movement imparted to the.

traverse guide 5 during the complete rotational movement of the cam 20. The line IIlI illustrates the uniform movement of the traverse guide 5 in one direction to an extreme positiony of its movement I03. After reversal of@ direction, the speed of the traverse guide 5 is increased as illustrated by the short line I04 after moving approximately 0.1 oi' its stroke. The movement of the traverse'guide is then continued in the same direction, as illustrated by line |05,- but at a speed approximately the same as that illustrated by line IIlI. This speed and direction is maintained to the opposite extreme end of its stroke after reversal at point |06. The traverse guide is moved in the opposite direction, as illustrated by line lill, but at the same speed as illustrated by line 194. As illustrated by second line IDI, the original speed and direction is then again resumed by the Itraverse guide.

' Figure 8 of the drawings illustrates by dotted line I 50 the approximate contour of a cake wound by the use of a traverse guide moving at a uniform 4speed throughout Iits traverse stroke cycle, when the traverse guide is spaced from the bobbin. The full line illustrates the general contour of a yarn package Wound in accordance with the'present invention- Figures 9 and l0 of the drawings illustrate a modified form ,of apparatus to be used when difficulty is encountered by -toofrequentacoincidence of succeeding thread layers sometimes referred to as ribbon winding." In this modification an eccentric is positioned to rotate within the traverse guide reciprocating cam. The modified apparatus comprises a reciprocating member 50 provided with a guide slot 52 and guide pin 56, the "guide slot and pin maintaining the member 50, in `a ysubstantialV reciprocating movement.

' The member 50 is also provided with a 1slot 54 in which the guide pin 58 attached' to the oscillating arm 26 is positioned. The cam followers- GIL-60 are attached to the reciprocating member 50. These cam followers are adapted tovfollow the cam surface of a plate cam 62. A rotating eccentric member 64 is positioned in crosshead 86 which in turn is positioned within slot 88 in the member 50. `The gear Gil is rotated by means of drive shaft E8. The gea-r 69 rotates gear 10 which in turnI rotates the shaft 56. The shaft 66 is freely rotatably mounted within eccentric 64 and is provided with a gear wheel 'I6 which is made to rotate gear 18 mounted on stub shaft 80.- Gear 82, which is also keyed to stub shaft 80, rotates gear 84 which is integral withveccenftric 64. yThe rotation of the eccentric within the crosshead. 86 causes a slight movement to be imparted to reciprocating member 50. The cam 62 is rotated by means of pin N, mountedv within the boss 12 integral with gear wheel 10. The eccentric movement of the cam will be superimposed upon the movement imparted to member 50 by cam 62, and since the cam and eccentric are rotated at different speeds the yarn helices on the bobbin will be spaced from each other without identical repetition except for possibly'l widely spaced intervals.

In the detailed apparatus above described, the.

traverse motion was imparted to the traverse guide by means of a plate cam in cooperation with connecting linkage mechanism. Obviously, a similar motion can be imparted to the traverse varm by the use of a suitable connecting linkage -and a grooved cam. The cam specifically described in the drawings is provided with two sections having a relatively high slopeand two sections with a relatively low slope (high speed` and low speed sections) Obviously, a cam may have four high slope sections and four low slope sec-l tions, it being only necessary that each high slope section have a. substantially equal and oppositely sloped high slope section, and each low slope section have an equal and oppositely sloped low slope section, and that the low slope sections alternate with the high slope sections.

From the above description it will be clear that the applicant obtains a package of uniform thick-- ness and density with a winding apparatus in which the traverse guide is spaced from the ro-A tating yarn support, by means of a single cam which imparts to the traverse guide a relatively slow motion in one direction to its extreme posi-` tion, then a reversal of direction, then a rela-` tively fast motion in the opposite direction, then a continuation of movement in the same direction. but at the slow motion above referred to. This last-named slow motion is continued to the opposite extreme position of dtstraverse then a reversal of directionthen at a relatively fast movement in the opposite direction, and then a resumption of the slow motion first referred to. The relatively slow movement of the traverse guide will take place over the major portion of its traverse stroke.

This invention provides a means of eliminating a large portion of the thread lag occurring at the reversal points of the traverse stroke of a wind-- ing machine wherein the traverse guide is mounted spaced from the surface of the wind-up package whereby the build-up of excessive; amounts of yarn at the shoulder portions of the'. package is avoided.

The invention provides a means whereby a` single primary cam can be used to actuate the traverse guide of the winding mechanism to form.

a yarn package of substantially uniform thick-`- ness and density.

The apparatus provided by the invention is;

simple toconstruct and economical to maintain.

spinning machine. However, the invention is not limited to use with such a machine, but is applicable to all types of winding mechanisms wherein the traverse guideis mounted spaced from the surface of the wind-up package.

Since it is obvious that many changes and modifications can be made in the details above described without departing from the nature and spirit of the invention, it is to be understood that the present invention is not to be limited to the said details except as set forth in the appended claims.

I claim:

1. The method of winding yarn on a rcfating yarn support `which comprises traversing the yarn with predetermined strokes in back and forth directions across the face of the support as the yarn is Wound thereon, a minor fraction of the length of the first portion of the traverse strokes in each direction of traverse being carried out at a higher speed than the remaining portion of said strokes.

2. The method of winding yarn on a rotating yarn support which comprises traversing the yarn with predetermined strokes in back and forth directions across the face of the support as the yarn is wound thereon, a minor fraction of the length of the first portion of the traverse strokes in each direction of traverse being carried out at a higher speed than the remaining portion of said strokes, said remaining portion of said strokes being carried out at a substantially uniform speed.

3. The method of Winding yarn on avrotating yarn support which comprises traversing the yarn with predetermined strokes in back and forth directions across the face of the support as the yarn is wound thereon, a minor fraction of the length of the first portion of the traverse strokes in each direction of traverse being carried out at a higher speed than the remaining portion of said strokes, the higher speed portion of the strokes being carried out at a substantially uniform speed, and said remaining portion of said strokes also being carried out at a substantially uniform speed.

4. The method of winding yarn on a rotating 4yarn support which comprises traversing the yarn with predetermined strokes in back and forth directions across the -faceof the support as the yarn is wound thereon, a minor fraction of the length of the first portion of the traverse strokes in each direction of traverse being carried out at a speed at least 20% greater than the speed of the remaining portion of said strokes.

5. In an apparatus for winding yarn, a rotating yarn support, a traverse arm including a traverse guide for traversing the yarn in back and forth directions across the face of said rotating support, said traverse arm spaced from said support, a cam, a cam follower connected to said traverse arm, said cam adapted to'impart to said traverse arm, movements of substantially uniform speed over the major portion of its traverse strokes to extreme positions in opposite directions, followed by movements, immediately after reversal of diy rection, over a minor portion of its traverse strokes at a higher speed.

6. In an apparatus for winding yarn, a rotatingy yarn support, a traverse arm including a traverse guide for traversing the yarn in back and forth directions across the face of said rotating support, said traverse arm spaced from said support, a cam, a cam follower connected to said traverse arm, said cam adapted to impart to said traverse arm, movements of substantially uniform speed over the major portion of its traverse strokes to extreme positions in opposite directions, followed by movements, immediately after reversal of direction, over a minor portion of its traverse strokesat a substantially uniform and higher' speed.

'7. In an apparatus for winding yarn/ as defined in claim 5 in which the camis a plate cam.

8. In an apparatus for winding yarn, a rotating yarn supporta traverse arm including a traverse guide for traversing the yarn in back' and forth said second-named section but in the direction of said first-named section, followed by a section identical with said first-named section, a' cam followerfconnected to. said traverse arm, said cam adapted to impart to said traverse ann movements of substantially uniform speed over the major portion of its traverse strolresl to extreme positions in opposite directions, followedV by movements, immediately after Ireversal of direction, overv a'minor portion of its traverse- ,strokes at a` higher 'speed'.

49. A wound yarn package the end portions of` which are comprised of yarn windings in which successive windings are alternately quick-traverse and slow-traverse windings.

10. A wound yarn package having slightly roundedend portions, saidend portions\com prised of yarn windings in which successive windings are alternately quick-traverse and slow-A 20 traverse-windings.

'WILLIS F. HICKES. 

